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<head>
    <meta charset="UTF-8">
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    <!-- 视口：为了适配移动端，宽度=设备宽度-->
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    <title>Document</title>
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    <style>

        *{
            padding: 0;
            margin:0;
        }
    /* 
        设计图稿

        750px                     375px      比例0.5               414px     比例是0.552
        元素宽高是                元素宽高是                      元素宽高是
        100px                      50px                            55.2px
    */

        div{
            width:50rem;
            height: 50rem;
            background:red;
        }
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